Fresh from claiming her 47th career title in Brisbane and with a rare calendar-year Grand Slam in her sights, she will ice her ankle and await the doctor's verdict.

An injured Williams will play into the hands of Azarenka, who six won WTA titles in 2012 but was forced to withdrew from Brisbane, where she was due to meet Williams in the semifinals, with a toe injury.

She showed little effect from the problem on Rod Laver Arena against Niculescu, but admitted she needed to yell at herself when she lost focus in the second set.

"It was just kind of to bring me back into competition, because I felt like the first set was really flowing my way and everything was going well for me. I was executing what I wanted," she said.

"And then, I kind of miss-hit a few shots and she got really competitive. I felt like I was on the practice court a little bit, letting go a few things that I shouldn't."

She next plays Eleni Daniilidou of Greece, with the other key player standing in the way of her title defence, Sharapova, in the other half of the draw.